Angelo Ogbonna, who was on the bench for the Champions League final in May, has twice won the Serie A title with Juventus but says he is eager to play under new West Ham boss Slaven Bilic.
"I wanted to play in the Premier League and am happy to be in London," Ogbonna told whufc.com. "My heart told me that the right decision was to play for West Ham United.
"I cannot wait to start working under Mr Bilic and with my new team-mates. I feel ready for this new adventure."